Catalytic Convert Confusion/Civic VX

[Davo53209@yahoo.com]

Latest update, about two days ago, I went to adjust the ignition timing on my car and prior to adjusting the timing, I'd noticed that the three indicator marks were advanced well past the mark on the timing cover. Whenever I had advanced the timing back to where I'd initially found it, the idle went down.

In my efforts, I was able to line up the red indicator mark perfectly to the indicator mark on the timing cover; but since then I'm noticing that the car back fires every now & again, in addition to the idle hovering round 900 rpm.

It's also been suggested to me by Eric The Car Guy, to first check the timing belt alignment, as that has a direct effect on ignition timing since the distributor is splined to the cam shaft. So far, I can't find an example as of how to do that.

Finally, I had recently taken the O2 sensor out of the old EX manifold that the former owner had rigged onto my car. When it came out, the sensor was black & sooty. Correct me if I'm wrong; but doesn't that mean that my car was running too rich?

I'm also starting to think that in addition to checking the alignment on the timing belt, I may also want to consider why the stock catalytic converter might have gone bad. With said, I would be open to suggestions as to what I should consider in terms of diagnostics.

Interestingly enough, at no time was I ever getting a check engine light while all of this was happening.

[vrmouseyd15b]

Jump the 2 wire thingy at the passenger floor. look for check engine flashing codes. If it doesn't come on at least solid, you're not doing it right.

My d15b was acting funny for a week with similar symptoms before it threw a solid code (knock sensor). It did give me the same code when I put the jumper, but otherwise nothing for a week.

Check your codes first.

[mechman600]

Originally Posted by Davo53209@yahoo.com

Do you think this aftermarket CAT will achieve the same mpg as an OEM part?

The cat will not affect economy. A/F ratio calculations are based on the upstream O2 sensor and are not affected by the presence or lack of a cat. Does your car have a downstream O2 sensor? If so, this one is only for cat efficiency calculations to determine whether the cat is doing its job or not.

Someone correct me if I am wrong.

[user removed]

The downstream (after the cat) 02 sensor is OBD2 which the VX never had. I don't think the cat position will affect the 02 sensor, but the sensor position needs to be where it originally was. Cat position COULD affect the 02 sensor if the residual heat from the cat kept the 02 sensor at a high enough temperature, which would makes sense because they put both cat and sensor about as close to the exhaust ports as they could.

regards
Mech

[mechman600]

Originally Posted by Old Mechanic

The downstream (after the cat) 02 sensor is OBD2 which the VX never had.

Noted.
My first point still stands. The presence or lack of a cat should not have an effect on fuel economy.

[user removed]

It's not an argument, just my opinion. They put the sensor and cat as close as they could to the exhaust ports and it COULD be for a reason or why not just use a common part for all the engines. 02 sensors need to be about 700+ degrees to function properly and in engines that run as lean as the VX, they may have known more than we do now.

regards
Mech

[mechman600]

Originally Posted by Old Mechanic

It's not an argument, just my opinion.

I wasn't arguing either. Just agreeing with you. I guess it came out wrong.

[Davo53209@yahoo.com]

As of yesterday, I had received my used exhaust manifold that I bought on Ebay, which came off of a 95 Honda Civic CX. Sure enough, it matches the part that I found on Majestic Honda.Com for my VX; but for only the mere price of $60.00 with shipping. I've cleaned up the majority of the rust, with pictures soon to follow.

As for the rest of my exhaust system, I've decided to go with a direct fit catalytic converter from Bosal, seeing how the stock OEM part was cost prohibitive. With everything said, I'm looking at just under $400.00 for the used manifold, CAT, down pipe & gaskets. Ideally, I'd like to source a used heat shield for the exhaust manifold; but that hasn't been easy to find.

Now regarding my other issue. I need to determine the root cause for my high idle, given that when I'd adjusted the ignition timing, I had lined up the red timing mark perfectly to the indicator mark on the timing cover.

With that under consideration, Eric The Car Guy had mentioned that I should check the alignment for the timing belt. Getting right to the point, I have no idea how to do that, nor can I find any examples on Youtube or the web that demonstrates the procedure. In fact, I don't even know what the expected result whether good or bad should be.

[vrmouseyd15b]

to check your timing belt alignment, you have to first line up the top dead center mark on your harmonic balancer with the arrows on the timing cover. Then you can remove the valve cover to get at your cam gear. There should be two cuts on the cam gear itself that will line up with the top section of the head. I believe on the stock cam gear there should also be an up arrow. Everytime I get into this, I end up buying a new valve cover gasket set with the spark plug seals. Its just under 20 bucks, and a great insurance policy.

I guess it could be possible bet your timing belt has stretched over time,you might be a half tooth off.

also, were you sure that you had the jumper in the connector under the passenger seat kick panel that would make the check engine light come on and have you in a position to be able to adjust your timing without the computer getting in the middle and screwing it all around on you?

top dead center mark on the harmonic balancer is the one mark by itself. the three marks that are closer together are for ignition timing those will be the ones you want to point at when you are looking with the timing light. timing light clip goes on the plug closest to the timing belt. make sure if your timing light clip has an arrow that indicates if it should point at the plug.

[vrmouseyd15b]

on the harmonic balancer, you want the one mark that is by itself, not the three that are together the three are for ignition timing. The one by itself is top dead center